package demo1;

public class LeetCode852 {
    public int peakIndexInMountainArray(int[] arr) {
        int left = 0, right = arr.length - 1;
        while(left < right) {
            int mid = left + (right - left + 1) / 2;
            if(arr[mid] < arr[mid - 1]) right = mid - 1;
            else left = mid;
        }
        return left;
    }
}
